Fluid operated pump



June 11, 1963 N. H. SACHNIK FLUID OPERATED PUMP 3 Sheets-Sheet 1 Filed Nov. 28, 1960 INVENTOR. NORMAN H. SACHNIK BY bowls 1L4 M ATTORNEY N. H. SACHNIK June 11, 1963 FIGIO 3,093,122 FLUID OPERATED PUMP Norman E. Sachnik, Houston, Tex., assignor to Texsteam Corporation Filed Nov. 28, 1960, Ser. No. 72,161 13 Claims. (Cl. 121-158) This invention relates in general to a fluid operated pump, and more particularly to a pump useful in any system wherein an absorbent or adsorbent fluid is injected into a process vessel and circulatedback from the process vessel whereby the energy of the circulated fluid may be utilized to drive the pump. Still more particularly, the pump of the present invention is adapted to operate with glycol dehydration units for removing moisture from natural gas, although other uses and purposes will be apparent to one skilled in the art of pumps.

The pump of the present invention is of the reciprocating type wherein pressurized fluid is employed for -driving the pump and means is provided to automatically control the driving pressurized fluid delivered to a single input port on the pump so as to effect reciprocal movement of the fluid pump piston. A master slide valve controls the distribution of the pressurized fluid to a power piston that is connected to a piston rod also common to the fluid pump piston. A pilot slide valve operable upon movement of the common piston rod controls operation of the master slide valve. Thus, a self-contained valving arrangement automatically controls the reciprocating action of the fluid pow-er piston for pumping fluid.

Accordingly, it is an object of this invention to provide an improved fluid operated reciprocating pump for pumping fluid and the like.

Another object of this invention is in the provision of a fluid operated pump having a relatively few number of parts and great simplicity thereby requiring a minimum amount of maintenance and attention.

Still another object of this invention is in the provision of a fluid operated reciprocating pump having a valving arrangement automatically operable during reciprocating action of the pump.

A further object of this invention is in the provision of a fluid operated pump especially useful in glycol dehydration units, wherein lean glycol is pumped into an absorber of a glycol dehydration unit and rich glycol from the absorber is utilized to drive the pump.

A still further object of this invention resides in the provision of a glycol operated pump for pumping lean glycol wherein the rich and lean glycol are completely isolated thereby preventing intermixing of same.

The pump of the present invention, operating in a glycol dehydration unit, minimizes the amount of gas consumed normally in driving a gas operated pump by substituting the high pressure fluid as part of the power media. Normally, in such a glycol dehydration unit, where the high pressure liquid is dumped from the high pressure to the low pressure vessel, conventional automatic liquid level controllers and dump valve arrangements are needed. Since the pump of the present invention utilizes the high pressure fluid as a powering agent, it is in some respects self-regulating in doing Work with the high pressure fluid as it is discharged from the vessel instead of merely throttling the liquid across a dump valve. This permits overall more economical construction cost of a dehydration unit because of the eliminating of the liquid level controller and the dump valve. Another feature of the invention is in that the pump is reciprocatory and that only one power chamber is pressurized and exhausted to cause such reciprocation. And although only a single power chamber is provided with other pumps of this type, the powering chamber usu- 3,093,122 Patented June 11, 1963 ally consists of two pistons or two sides of the same piston to cause the pump to be forced in one direction and then in the other direction by reversing the pressures across the piston. Invariably, this arrangement involves a certain amount of clearance volume on both sides of the piston.

Therefore, it is a further object of this invention to provide a fluid operated pump for use in glycol dehydration units which is self-regulating and functions to eliminate liquid level controllers and dump valve arrangements in order to provide a more economical construction.

Another object of this invention resides in the provision of a fluid operated pump having a single power chamber, wherein the clearance volume for the chamber has been eifectively reduced to approximately one-half of that which would be used in a duplex power chamber, thereby reducing the amount of power fluid required to cause the pump to reciprocate.

A still further object of this invention is to provide a fluid operated pump which has only one power chamber thereby simplifying the switching mechanism or slide arrangements for operating the pump wherein only a twoported slide is necessary.

Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts, in which:

FIG. 1 is a top plan view of the pump of the present invention with some parts broken away for purposes of clarity;

FIG. 2 is a longitudinal sectional view taken through the pump of FIG. 1 showing some parts in elevation and other parts broken away for purposes of clarity;

FIG. 3 is an enlarged detail sectional view taken substantially along line 3-3 of FIG. 2;

FIG. 4 is an enlarged transverse sectional view, taken substantially along line 4-4 of FIG. 2;

FIG. 5 is an enlarged transverse sectional view taken substantially along line 5-5 of FIG. 2;

PH. 6 is an enlarged detail sectional view taken substantially along line 6-6 of FIG. 2;

FIG. 7 is an enlarged detail sectional view taken substantially along line 77 of FIG. 2;

FIG. 8 is an enlarged transverse sectional view taken substantially along line 8-8 of FIG. 2;

FIG. 9 is an enlarged top plan view of the pilot valve plate; and

FIG. 10 is a transverse sectional view of the master valve plate, taken substantially along line 10-10 of FIG. 1.

The pump of the present invention may be used in any system for pumping absorbent or adsorbent fluid into a process vessel, wherein the fluid is returned from the process vessel under higher pressure to drive the pump, although the pump of the present invention will be described in association with a glycol dehydration unit. Accordingly, in general, the pump is intended to inject lean glycol into a glycol absorber of a glycol dehydration unit. The power required to operate the pump is received in the form of high pressure, rich glycol from the absorber, which contains absorbed water and hydrocarbon vapors. A certain amount of high pressure gas from the absorber is also entrained in the rich glycol which is used to drive the pump.

Referring now to the drawings, the pump body includes generally a power cylinder it a fluid end adapter 11 at one end of the power cylinder, a valve end adapter 12 at the other end of the power cylinder, a fluid cylinder 13 extending from the end of the fluid end adapter 11 remote from the power cylinder, a suction head 14 covering the end of the fluid cylinder remote from the fluid end adapter 11, a pilot valve body extending from the end of the valve end adapter 12 remote from the power cylinder, and a master valve body 16 secured to the pilot valve body 15. The end of the pilot valve body 15 adjacent the valve end adapter 12 and the suction head 14 are provided with flanges for receiving tie rods that serve to hold in tightly assembled position the power cylinder 19, fluid end adapter 11, valve end adapter 12, fluid cylinder 13, suction head 14 and pilot valve body 15. The master valve body 16 is independently secured to the pilot valve body 15.

The power cylinder This provided with a bore 17 which slidably receives a power piston 18 which is annular in shape and provided with a center bore 19 receiving a common piston rod 29 which extends through and into the power cylinder 10, the fluid end adapter 11, the valve end adapter 12, the fluid cylinder 13, and the pilot valve body 15. A pair of power piston rings 18a are carried on the power piston 18 for sealing engagement with the bore 17 of the power cylinder. Similarly, an O-ring 23 is provided between the power piston 13 and the piston rod to prevent leakage of fluid along the piston rod and the piston. The power piston 18 is held in position along the piston rod 20 by means of a piston retainer ring 24 locking the power piston against movement toward the left as viewed in the drawings, and an elongated sleeve 25 received over the piston rod and abutting against the other side of the power piston. A bushing 26 is screw threaded into the outer open end of a blind bore 27 formed in the right hand end of the piston rod 29, and defines a flange for receiving a sleeve retainer ring 28 to lock the sleeve 25 in position along the piston rod 20 and thereby lock the power piston 18 on the piston rod. An O-ring Z9 is provided between the outer surface of the piston rod and the inner surface of the sleeve 25 to prevent leakage of fluid along the surfaces between the sleeve and piston rod.

The power cylinder 10 is closed at one end by the fluid end adapter 11 thereby defining a chamber 30 at one side of the power piston 18. An O-ring 31 is arranged between the fluid end adapter 11 and the power cylinder 1%) to prevent leakage of fluid therebetween. An annular recess is provided within the fluid end adapter 11 for receiving packing 32 which sealingly surrounds the piston rod 20. A packing retainer bushing 33 holds the packing 32 in position and is, in turn, maintained in position in the fluid end adapter by abutting against one end of the fluid cylinder 13 which extends from the fluid end adapter away from the power cylinder 10. Thus, fluid leakage along the piston rod and the fluid end adapter is sealed off by the packing 32. An inlet port 35 is provided in the fluid end adapter and communicates with the power chamber 30.

The other end of the power cylinder 10 is closed by the valve end adapter 12 which is annularly internally recessed to receive a power end packing 37 for effecting a fluid seal against the sleeve 25 on the piston rod 20. The pilot valve body 15 holds the packing 37 in position in a recess of the valve end adapter 12 and is sealed against fluid leakage therewith by an O-ring 38. An O-ring 39 seals against fluid leakage between the valve end adapter 12 and the power cylinder 10. Thus, the valve end adapter 12 coacts to define a chamber 40 at the other side of the power piston 18.

Fluid leakage between the fluid end adapter 11 and the fluid cylinder 13 is prevented by an O-ring 41. The fluid cylinder 13 is provided with a bore 42 which slidably receives a fluid piston 43 suitably secured to the end of the piston rod 20. Piston rings 44 are received on the outer circumference of the fluid piston 43 for sealing engagement with the bore 42 of the fluid cylinder. The fluid piston 43 is secured to the end of the piston rod by a retaining bushing 45 screw threaded into a bore 46 formed in the end of the piston rod. An O-ring 47 precludes fluid leakage between the fluid piston 43 and the piston 4 rod 20. A chamber 48 is defined in the fluid cylinder with the fluid piston 43 and the fluid end adapter 11.

The suction head 14 closes the other end of the fluid cylinder 13 and defines at the other side of the piston 43 a chamber 49. Fluid leakage between the fluid cylinder 13 and the suction head is prevented by an O-ring 50.

A laterally extending bore 51 is provided in the suction head 14 and communicates at its inner end with the chamber 49 in the fluid cylinder. The bore 51 is threaded at its lower end and threadedly receives a suction bushing 52. A poppet check valve 53 is guidably carried in the bushing and provided with an O-ring 54 that coacts with an inclined annular seat on the upper end of the bushing to define a liquid seal between the poppet check valve and the bushing. An inlet bore 55 extends through the bushing 52 which is adapted to be connected to a supply of lean glycol. The lower end of the poppet valve 53 is tubular and provided with a plurality of openings 56, FIGS. 2 and 3, which permit flow of glycol between the inlet bore 55 and the chamber 49 when the poppet valve is raised from its seat. When fluid in chamber 49 is pressurized by movement of the piston rod 20 towards the left, the poppet valve closes to prevent backward flow of fluid through the inlet bore 55. Thus, the poppet valve only permits fluid flow in one direction, that is, into the chamber 49 of the fluid cylinder. By action of the fluid piston 43 in the fluid cylinder toward the right as seen in the drawing, a supply of lean glycol is sucked into the chamber 49. A bleed valve 58 is provided to properly condition the pumping chamber 49.

Upon stroking of the piston rod and piston 43 toward the left, during which time the poppet valve 53 is seated and prevents pumping of the lean glycol out of the inlet 55 and the chamber 49, the lean glycol is forced into the chamber 48. Transfer of the lean glycol from the chamber 49 into the chamber 48 is provided by means of a passageway 59 in the bushing 45 which communicates with a necked-down portion 46a of the bore 46 that, in turn, communicates with a transverse passageway 60 extending entirely through the piston rod 20. From the chamber 48, lean glycol is pumped through an outlet 61 in the fluid end adapted 11 to an absorber of a dehydration unit. The outlet 61 is in communication with the chamber 48, and to prevent passage of the fluid in the chamber 48 back to the chamber 49 during stroking of the fluid piston toward the right, a ball check valve 63 is provided at the inner end of the bushing 45 to seat against a surface 64 at the inner end of the passageway 59. A coil spring 65 resiliently biases the ball check valve 63 against the seating surface 64.

The pilot valve body 15 is provided with a blind bore defining a chamber 66 adapted to receive the piston rod 20, and a slide valve chamber 67 spaced therefrom and intercommunicating with the chamber 66 by a passageway 68. The chamber 67 communicates thereabove with an opening 69 extending upwardly and through the upper side of the valve body 15. The valve body opening 69 receives a pilot valve plate 70 having spaced ports 71 and 72 coacting with a pilot slide valve 73 for controlling movement of fluid into the master valve body.

An elongated pilot valve rod is generally designated by the numeral 74 and includes an elongated section 75 received in the chamber 66 and freely received in a bore 76 provided in the bushing 26, an enlarged bearingly supported portion 77 slidably received in a bearing 78, and an end section 79 receiving the part of the slide valve 73. An enlarged head 80 is carried on the end of the section 75 remote from the end of the rod carrying the pilot slide valve to coact with the piston rod 20 and effect a lost motion connection therebetween for controlling operation of the pilot slide. An inlet port 81 is provided in the pilot valve body and connects to a conduit 81a which receives rich glycol under pressure from the absorber of the dehydration unit. Thus, the inlet port 81 receives the power supply for driving the pump. Action of the pilot valve rod 74 is such that upon stroking of the piston rod 20 toward the right, the shoulder 80a of the enlargement 80 is engaged by the bottom wall 83 of the blind bore 27 to move the valve rod toward the right and align the closed pocket 73a of the slide valve so as to intercommunicate ports 71 and 72 and isolate the chamber 67 from either of the ports. Upon stroking of the piston rod 20 toward the left, the inner end 26a of the bushing 26 strikes the other end 80b of the enlargement 80 and carries the valve rod 74 to the left to the position approximately shown in the drawing wherein the port 72 is intercommunicated with the chamber 67 and the port 71 is isolated with respect to the chamber 67 by virtue of the pilot slide valve 73.

Fluid leakage between the pilot valve plate 70 and the pilot valve body 15 is prevented by an O-ring seal 82 arranged therebetween. The pilot valve plate 70 is locked into position by the overlapping of the master valve body 16 which is arranged over the pilot valve body 15 and suitably secured thereto.

The master valve body includes a master slide valve 84 which controls the operation of the power piston 18 and is, in turn, controlled by action of the pilot slide valve 73. A chamber 85 is formed in the master valve body 16 and opens to the upper side thereof and is closed by a master valve plate 86. The master slide valve 84 is mounted on one end of a master Valve rod 87 slidably received in a bore 88 formed in the master valve body. A pin 84b serves to properly secure the slide valve 84 to the rod 87.

The master valve body includes a bore 90 at the right hand end which receives a piston sleeve 91. A master valve piston 92 is slidably received in the piston sleeve 91 and suitably connected to the master valve rod 87. Master valve rod packing 93 is sealingly arranged about the master valve rod 87 and held in position by a packing retainer ring 94. The left end of the piston sleeve 91' abuts against the remainer ring 94 and is held in place by a master valve cap 95 which is threadedly received in the end of the bore 90. A suitable O-ring may be provided toseal the master valve cap to the master valve body.

The opposite ends of the piston sleeve 91 are circumferentially perforated or provided with openings 96 and 97 in alignment with annular grooves 98 and 99 provided in the bore 90 of the master valve body. An O-ring 90a is provided between the piston sleeve 91 and the bore 90 in order to prevent fluid leakage therealong and between the annular grooves 98 and 99. Suitable packing may be provided on the piston 92 to provide a sealing relationship between the piston and the sleeve 91. A power chamber 100 is defined between the right hand side of the piston 92 and the master valve cap 95, while an exhaust chamber 101 is defined between the other side of the piston 92 and the packing retainer ring 94. The power chamber 100 is in communication with an inlet port 102 formed in the master valve body, while the exhaust chamber 101 is in communication with an exhaust port 103 formed in the master valve body and an exhaust outlet 104. The inlet port 102 is in alignment with an enlarged opening formed in the upper face of the pilot valve plate 70 and which is in communication with the port 72 of the pilot valve, while the exhaust port 103 is in communication with an enlarged opening formed in the upper face of the pilot valve plate which is in communication with the port 71 therein. It may be noted that the port 71 is at all times in communication with the exhaust outlet 104. A pin 105 is provided to lock the pilot valve plate 70 to the pilot valve body. It may be noted that the port 72 in the pilot valve plate leads to the power chamber 100 in the master valve body. Further, the port 72 selectively interconnects the chamber 67 in the pilot valve body with the power chamber 100 when the pilot valve 73 is positioned as shown in FIG. 2.

When the pilot slide valve moves to the right, the power chamber 100 is intercommunicated with the ex- 8 haust chamber 101 through the exhaust port 71. An O-ring 106 fluid seals the exhaust port 71 of the pilot valve plate 70 with the exhaust port 103 in the master valve \body 16, while an O-ring 107 fluid seals the port 71 in the pilot valve plate with the inlet port 102 in the master valve body.

The chamber 85 in the master valve body 16 intercommunicates with the chamber 66 in the pilot valve body by means of the port 108 in the master valve body aligning with a port 109 in the pilot valve body. An O-ring 110 prevents fluid leakage between the master valve body and the pilot valve body around the ports 108 and 10 9. An outlet port 111 in the master valve plate 86 in-tercommunicates with the chamber 85 and leads to one side of a speed control valve '34 threadedly mounted in a bore in the master valve body. A conduit or line 112 connects the other side of the master control valve to the inlet port 35 of the power chamber 30 in the power cylinder. The speed control valve 34 is provided for controlling the speed of the pump by controlling the flow of fluid into and out of the power chamber 30. The pocket 84a of the master slide valve 84 is in constant communication with an exhaust port 114 formed in the master valve plate 86. In the position shown in FIG. 2, the master slide valve isolates exhaust port 114 from the chamber 85 and the port 111. Upon movement of the master slide valve 84 toward the right, the ports 1-11 and 114 are interconnected and the chamber 85 is isolated from the port 111. An O-ring '115 is arranged between the master valve body and the master valve plate in order to prevent fluid leakage :therebetween.

While the chamber 30 of the power cylinder interconnects with the power line 112, it may be noted that the chamber 40 on the other side of the power piston 18 intercommunicates with an exhaust port 116 that connects to an exhaust conduit 117 that, in turn, is connected to a T-fitting 1-13 mounted in the master valve body 16 and at one end of a transversely extending bore, FIG. 10. An exhaust line 22 is connected to the other end of the bore. A conduit or line 118 connects the exhaust outlet 104 with the ff-fitting 1-13 and ultimately to the exhaust line 22.

-In operation, with the parts shown as in the drawing, rich glycol under pressure is admitted through the line 81a to the inlet port 81 and into the chambers 66 and .67, whereupon it is delivered through ports 10 9 and 108 to the chamber 85 of the master valve body and through the speed control valve 34 and the power conduit 112 to the chamber 30 of the power cylinder for driving the power piston 18 and the piston rod toward the right as viewed in the drawing. At the same time, the high pressure rich glycol is in communication with the chamber 100 of the master valve cylinder through chamber 67, ports 72 and 102 and openings 97 and holds the master slide valve in position as shown in FIG. 2 because the unbalance of area against the piston 92 is greater than the area of the end of the piston rod 8-7 and designated by the numeral 87a in the chamber 85. It wil be appreciated that clearance exists between the end 87a and the adjacent end of the valve body. As the piston rod is driven toward the right, lean glycol is drawn into the inlet port 55 and into the chamber 49, while the lean glycol in the chamber 48 is pumped out through the discharge port 61 and to the absorber. When the bottom 83 of the blind bore 27 in the piston rod 20 strikes the free end a of the enlargement 80 on the end of the pilot valve rod 74, continued movement of the piston rod toward the right will move the pilot slide valve 73 to the right to intercomrnunicate ports 71 and 72 thereby intercomrnunicating the chamber 100 with the exhaust line 22, at which time the high pressure rich glycol in the chamber will act against the end 87a of the piston rod 87 to drive the piston rod and master slide valve 84 to the right so as to intercommunicate the exhaust port 114 and port 111 in the master valve plate and shut off the supply of high pressure rich glycol to the chamber 30 and the power cylinden.

Thus, movement of the master slide valve to the right to the point that it intercommunicates ports 111 and 114 eflectively intercommunicates the chamber 30 of the power cylinder with the exhaust line 22.

The high pressure rich glycol always present in the chamber 66 will then act against the end of the piston rod 20 in the chamber 66 and drive the piston rod 20 toward the left thereby causing the glycol in the chamber 30 to be exhausted into the exhaust line 22, and further cause closure of the poppet check valve 53 and opening of the ball valve 63 to transmit the fluid in chamber 49 into chamber 48, and thereby forcing a volume of fluid, out through the outlet port 61. This volume of fluid discharged as the piston rod 20 moves from right to left is equal to the displacement 'of the piston rod 20. At the end of the stroke, the inner end 26:: of the bushing 26 will engage the inner end 80b of the enlargement 80 on the end of the pilot valve rod 74 to drive the pilot slide valve 73 to the left and once again open the port 72 to the chamber 67 and thereby intercommunicate chamber 67 with the chamber 100. With the rich, high pressure glycol then being delivered to the chamber 100, and because of the larger area on the slide valve piston than the end 87a of the rod 87, the slide valve piston rod 87 will be driven toward the left to again intercommunicate the port 111 with the chamber 85 and once again deliver rich, high pressure glycol to the chamber 30 of the power cylinder for repeating the cycle of operation and driving the power piston 18 and piston rod 20 toward the right again. The cycle of operation then repeats itself.

In driving the power piston 18 to the right as seen in FIG. 2, it should be appreciated that the pressure-area component against the power piston 18 must be greater than the pressure-area component against the end of the piston rod 20 in the chamber 66' plus the pressure-area component against the fluid piston 43 in the chamber 48. Likewise, when the pump is conditioned by the valves to move toward the left in FIG. 2, the pressure-area component against the piston rod 20 in chamber 66 must be greater than the pressure-area component against the end of the fluid piston 43 in the chamber 49 plus the now exhaust pressure-area component against the power piston in the chamber 30.

It will be understood that modifications and variations may be eifected without departing from the scope of the novel concepts of the present invention, but it is understood that this application is to be limited only by the scope of the appended claims.

The invention is hereby claimed as follows:

1. A fluid operated motor adapted to drive a pump,

said motor comprising a piston rod having a power piston thereon, a high pressure fluid chamber having one end of the piston rod received therein, means for supplying high pressure fluid to said chamber whereby the end of the piston rod therein is continually subjected to the,

pressure of said fluid, a master slide valve for selectively interconnecting said chamber to the side of said power piston opposite from said one end of said piston rod, fluid operated means for driving said master slide valve, a pilot slide valve controlling said fluid operated means for selectively actuating said master slide valve, and means interconnecting said piston rod and. pilot slide valve to actuate said pilot slide valve concurrently with the reciprocation of said piston rod.

2. A fluid operated motor adapted to drive a pump, said motor comprising a piston rod having a power piston thereon, a high pressure fluid chamber having one end of the piston rod received therein, means for supplying high pressure fluid to said chamber whereby the end of the piston rod therein is continually subjected to the pressure of said fluid, a master slide valve for selectively interconnecting said chamber to the side of said power piston opposite from said one end of said piston rod, fluid operated means for driving said master slide valve,

a pilot slide valve controlling said fluid operated means for selectively actuating said master slide valve, and a lost motion connection between said piston rod and pilot slide valve to actuate said pilot slide valve concurrently with the reciprocation of said piston rod.

3. A fluid operated motor adapted to drive a pump, said motor comprising a piston rod having a power piston thereon, a high pressure fluid chamber having one end of the piston rod received therein, means for supplying high pressure fluid to said chamber whereby the end of the piston rod therein is continually subjected to the pressure of said fluid, a master slide valve for selectively interconnecting said chamber to the side of said power piston opposite from said one end of said piston rod, fluid operated means for driving said master slide valve, a pilot slide valve controlling said fluid operated means for selectively actuating said master slide valve, and a lost motion connection between said piston rod and pilot slide valve to actuate said pilot slide valve at the opposite ends of the reciprocal stroke of said piston rod.

4. A fluid operated motor adapted to drive a pump, said motor comprising a power cylinder and a high pressure fluid chamber, a piston rod extending into said power cylinder and having an end terminating in said fluid chamber, a piston on said rod and reciprocal in said power cylinder, means for supplying high pressure fluid to said fluid chamber whereby said piston rod end is continually subjected to the pressure of the fluid, first valve means for selectively interconnecting said fluid chamber and the side of the power piston in said power cylinder to drive the piston rod into said fluid chamber, fluid operated means for driving said master slide valve, second valve means controlling said fluid operated means for selectively actuating said first valve means, and means interconnecting said piston rod and said second valve means to actuate said second valve means concurrently with the reciprocation of said piston rod.

5. A fluid operated motor adapted to drive a pump, said motor comprising a power cylinder and a high pressure fluid chamber, a piston rod extending into said power cylinder and having an end terminating in said fluid chamber, a piston on said rod and reciprocal in said power cylinder, the pressure area of said power cylinder being greater than the pressure area on the end of said piston rod in said fluid chamber, means for supplying high pressure fluid to said fluid chamber whereby said piston rod end is continually subjected to the pressure of the fluid, first valve means for selectively interconnecting said fluid chamber and the side of the power piston in said power cylinder to drive the piston rod into said fluid chamber, fluid operated means for driving said master slide valve, second valve means controlling said fluid operated means for selectively actuating said first valve means, and means interconnecting said piston rod and said second valve means to actuate said second valve means concurrently with the reciprocation of said piston rod.

6. A fluid operated motor adapted to drive a pump, said motor comprising a power cylinder and a high pressure fluid chamber, a piston rod extending into said power cylinder and having an end terminating in said fluid chamber, a piston on said rod and reciprocal in said power cylinder, means for supplying high pressure fluid to said fluid chamber whereby said piston rod end is continually subjected to the pressure of the fluid, first valve means for selectively interconnecting said fluid chamber and the side of the power piston in said power cylinder to drive the piston rod into said fluid chamber, second valve means for selectively actuating said first valve means, means interconnecting said piston rod and said second valve means to actuate said second valve means concurrently with the reciprocation of said piston rod, and control valve means between said fluid chamber and said power cylinder to control the fluid flow therebetween thereby controlling the speed of said motor.

7. A fluid operated motor adapted to drive a pump,

said motor comprising a power cylinder and a high pressure fluid chamber, a piston rod extending into said power cylinder and having an end terminating in said fluid chamber, a piston on said rod and reciprocal in said power cylinder, the pressure area of said power cylinder being greater than the pressure area on the end of said piston rod in said fluid chamber, means for supplying high pressure fluid to said fluid chamber whereby said piston rod end is continually subjected to the pressure of the fluid, first valve means for selectively interconnecting said fluid chamber and the side of the power piston in said power cylinder to drive the piston rod into said fluid chamber, fluid operated means for driving said master slide valve, second valve means controlling said fluid operated means for selectively actuating said first valve means, and lost motion connecting means interconnecting said piston rod and said second valve means to actuate said second valve means at the extreme ends of the reciprocal stroke of said piston rod.

8. A fluid operated motor adapted to drive a pump, said motor comprising a power cylinder and a high pressure fluid chamber, a piston rod extending into said power cylinder and having an end terminating in said fluid chamber, a piston on said rod and reciprocal in said power cylinder, the pressure area of said power cylinder being greater than the pressure area on the end of said piston rod in said fluid chamber, means for supplying high pressure fluid to said fluid chamber whereby said piston rod end is continually subjected to the pressure of the fluid, a reciprocating master slide valve for selectively interconnecting said fluid chamber and the side of the piston in the power cylinder remote from said piston rod end or interconnecting an exhaust line and the side of the piston in the power cylinder remote from said piston rod end, a reciprocating pilot slide valve for selectively actuating said master slide valve, and a lost motion connection between said piston rod and pilot slide valve to actuate said pilot slide valve concurrently with the reciprocation of said piston rod.

9. A fluid operated motor adapted to drive a pump, said motor comprising a power cylinder and a high pressure fluid chamber, a piston rod extending into said power cylinder and having an end terminating in said fluid chamber, a piston on said rod and reciprocal in said power cylinder, the pressure area of said power cylinder being greater than the pressure area on the end of said piston rod in said fluid chamber, means for supplying high pressure fluid to said fluid chamber whereby said piston rod end is continually subjected to the pressure of the fluid, a twin-ported reciprocating master slide valve for selectively interconnecting said fluid chamber and the side of the piston in the power cylinder remote from said piston rod end or interconnecting an exhaust line and the side of the piston in the power cylinder remote from said piston rod end, a twin-ported reciprocating pilot slide valve for selectively actuating said master slide valve, and a lost motion connection between said piston rod and pilot slide valve to actuate said pilot slide valve concurrently with the reciprocation of said piston rod.

10. A fluid operated motor adapted to drive a pum said motor comprising a power cylinder and a high pressure fluid chamber, a piston rod extending into said power cylinder and having an end terminating in said fluid chamber, a piston on said rod and reciprocal in said power cylinder, the pressure area of said power cylinder being greater than the pressure area on the end of said piston rod in said fluid chamber, means for supplying high pressure fluid to said fluid chamber whereby said piston rod end is continually subjected to the pressure of the fluid, a twin-ported reciprocating master slide valve for selectively interconnecting said fluid chamber and the side of the piston in the power cylinder remote from said piston rod end or interconnecting an exhaust line and the side of the piston in the power cylinder remote from said piston rod end, a twin-ported reciprocating pilot slide valve for selectively actuating said master slide valve, a lost motion connection between said piston rod and pilot slide valve to actuate said pilot slide valve concurrently with the reciprocation of said piston rod, and control valve means between said fluid chamber and said power cylinder to control the fluid flow therebetween thereby controlling the speed of said motor.

11. A fluid ope-rated motor adapted to drive a pump, said motor comprising a power cylinder, a high pressure fluid supply chamber having an inlet thereto, a master valve and a pilot valve, said power cylinder having a power piston reciprocable therein, an inlet port, and an exhaust port, said master valve having a master valve chamber, means intercommunicating said supply chamher and said master valve chamber, a first port connected to an exhaust line, a second port connected to the inlet port of said power cylinder, a master slide valve in said master valve chamber for selectively isolating said first port and intercornrnunicating said second port to said master valve chamber or interconnecting said first and second ports, a master valve rod reciprocably mounted in said master valve chamber and carrying said master slide valve, a master valve cylinder adjacent said master valve chamber having a master valve piston reciprocable therein engage-able with one end of said master valve rod to drive said rod and master slide valve to the position whereby said first port is isolated, said master valve cylinder having an exhaust port on one side of the master vmve piston and an inlet port on the other side thereof, said pilot valve including a pilot valve chamber, means intercommunicating said pilot valve chamber and said supply chamber, a first pilot valve port interconnected to the exhaust side of said master valve piston, a second pilot valve port interconnected to the inlet side of said master valve piston, a pilot slide valve insaid pilot valve chamber for selectively isolating said first pilot valve port and intercommunicating said second pilot valve port to said pilot valve chamber or interconnecting said first and second pilot valve ports, a pilot valve rod reciprocably mounted in said pilot valve chamber, a connecting rod carried by said power piston, one end of said connecting rod extending into said supply chamber, and a lost motion connection between said pilot valve rod and said connecting rod for reciprocating the pilot valve rod at the ends of the reciprocal stroke of said connecting rod.

12. A fluid operated motor adapted to drive a pump, said motor comprising a power cylinder, a pressure fluid supply chamber having an inlet thereto, a master valve and a pilot valve, said power cylinder having a power piston reciprocable therein, an inlet port, and an exhaust port, said master valve having a master valve chamber, means intercommunicating said supply chamher and said master valve chamber, a first port connected to an exhaust line, a second port connected to the inlet port of said power cylinder, a master slide valve in said master valve chamber for selectively isolating said first port and intercomrnunicating said second port to said master valve chamber or interconnecting said first and second ports, a master valve rod reciprocably mounted in said master valve chamber and carrying said master slide valve, a master valve cylinder adjacent said master valve chamber having a master valve piston reciprocable therein engageable with one end of said master valve rod to drive said rod and master slide valve to the position whereby said first port is isolated, said master valve cylinder having an exhaust port on one side of the master valve piston and an inlet port on the other side thereof, said pilot valve including a pilot valve chamber, means intercommunicating said pilot valve chamber and said supply chamber, a first pilot valve port interconnected to the exhaust side of said master valve piston, a second pilot valve port interconnected to the inlet port side of said master valve piston, a pilot slide valve in said pilot valve chamber for selectively isolating said first pilot valve port and intercommunicating said second pilot valve port to said pilot valve chamber or interconnecting said first and second pilot valve ports, a pilot valve rod reciprocably mounted in said pilot valve chamber, a connecting rod carried by said power piston, one end of said connecting rod extending into said supply chamber, and a lost motion connection between said pilot valve rod and said connecting rod for reciprocating the pilot valve rod at the ends of the reciprocal stroke of said connecting rod, the pressure area of said power piston being greater than the pressure area of said connecting rod end in said supply chamber.

13. A fluid operated motor adapted to drive a pump, said motor comprising a power cylinder, a high pressure fluid supply chamber having an inlet thereto, a master valve and a pilot valve, said power cylinder having a power piston reciprocable therein, an inlet port, and an exhaust port, said master valve having a master valve chamber, means intercommunicating said supply chamber and said master valve chamber, a first port connected to an exhaust line, a second port connected to the inlet port of said power cylinder, a master slide valve in said master valve chamber for selectively isolating said first port and intercommunicating said second port to said master valve chamber or interconnecting said first and second ports, a master valve rod reciprocably mounted in said master valve chamber and carrying said master slide valve, a master valve cylinder adjacent said master valve chamber having a master valve piston reciprocable therein engageable with one end of said master valve rod to drive said rod and master slide valve to the position whereby said first port is isolated, said master valve cylinder having an exhaust port on one side of the master valve piston and an inlet port on the other side thereof, said pilot valve including a pilot valve chamber, means intercommunicating said pilot valve chamber and said supply chamber, a first pilot valve port valve in said pilot valve chamber for selectively isolating said first pilot valve port and intercommunicating said second pilot valve port to said pilot valve chamber or interconnecting said first and second pilot valve ports, a pilot valve rod reciprocably mounted in said pilot valve chamber, a connecting rod carried by said power piston, one end of said connecting rod extending into said supply chamber, and a lost motion connection between said pilot valve rod and said connecting rod for reciprocating the pilot valve rod at the ends of the reciprocal stroke of said connecting rod, the pressure area of said power piston being greater than the pressure area of said connecting rod end in said supply chamber and the pressure area of the outlet side of said piston.

References Cited in the file of this patent UNITED STATES PATENTS 825,950 Weir July 17, 1906 2,087,713 Whiteside et a1 July 20, 1937 2,215,852 Klein Sept. 24, 1940 2,490,000 Cooper Nov. 29, 1949 2,538,842 McFarland Jan. 23, 1951 2,631,572 Dempsey Mar. 17, 1953 2,637,304 Dinkelkomp May 5, 1953 2,707,456 Schweisthal May 3, 1955 2,751,889 Mohler June 26, 1956 2,989,077 Lee June 20, 1961 FOREIGN PATENTS 5,243 Great Britain 190] 

1. A FLUID OPERARTED MOTOR ADAPTED TO DRIVE A PUMP, SAID MOTOR COMPRISING A PISTON ROD HAVING A POWER PISTON THEREON, A HIGH PRESSURE FLUID CHAMBER HAVING ONE END OF THE PISTON ROD RECEIVED THEREIN, MEANS FOR SUPPLYING HIGH PRESSURE FLUID TO SAID CHAMBER WHEREBY THE END OF THE PISTON ROD THEREIN IS CONTINUALLY SUBJECTED TO THE PRESSURE OF SAID FLUID, A MASTER SLIDE VALVE FOR SELECTIVELY INTERCONNECTING SAID CHAMBER TO THE SIDE OF SAID POWER PISTON OPPOSITE FROM SAID ONE END OF SAID PISTON ROD, FLUID OPERATED MEANS FOR DRIVING SAID MASTER SLIDE VALVE, A PILOT SLIDE VALVE CONTROLLING SAID FLUID OPERATED MEANS FOR SELECTIVELY ACTUATING SAID MASTER SLIDE VALVE, AND MEANS INTERCONNECTING SAID PISTON ROD AND PILOT SLIDE VALVE TO ACTUATE SAID PILOT SLIDE VALVE CONCURRENTLY WITH THE RECIPROCATION OF SAID PISTON ROD. 